Cathode ray tube with axially separable tube means for mounting the electrodes therein



A. BELL 3,529,196 CATHODE RAY TUBE WITH AXIALLY SEPARABLE TUBE MEANS FOR Sept. 15, 1970' MOUNTING THE ELECTRODES THEREIN 3 Sheets-Sheet .1

Filed July 19, 1968 ,u M mm eM/W \t w mm wm mm mm M: w F A I !l 1 [:1 l I l 111 I) m v 2 -93 mm vw ATTORNEYS A. BELL CATHODE RAY TUBE WITH AXIALLY SEPARABLE TUBE MEANS FOR Sept. 15, 1970 MOUNTING THE ELECTRODES THERBIN 3 sheets shcet 1.

Filed July 19, 1968 hm hm INVENTOE ALEXANDER BELL Z/z/ ATTOENEY5 United States Patent US. Cl. 31382 11 Claims ABSTRACT OF THE DISCLOSURE A cathode ray tube is described including a plurality of internal elements supported in a surrounding coaxial ceramic tube. Some of the internal elements are of larger diameter than the others and the ceramic tube has a correspondingly larger diameter portion at these elements and is axially separable at the larger portion.

This invention relates to cathode ray tubes and, more particularly, to an improved cathode ray tube having provision for supporting internal elements of different diameters.

Cathode ray tubes for display, scan conversion or similar purposes generally include a tube envelope of glass or metal, a target screen or surface, and one or more elec tron gun assemblies. The electron gun assemblies generate electron beams which are directed against the target screen or surface to energize predetermined areas thereof in accordance with a desired pattern. An electron gun assembly is frequently disposed within a constricted neck of the tube envelope and includes a plurality of elements for forming and controlling the electron beam. Some of these elements may serve to deflect the beam to impinge upon certain areas of the screen, or to focus the beam for sharpness of image. Other elements may be utilized to vary the intensity of the beam and thus control the brightness of the display, or to vary the cross sectional shape of the beam to cause the energized area on the screen to assume a corresponding shape.

During the manufacture of cathode ray tubes of the type described, it is usually necessary that the various internal forming and controlling elements be accurately aligned and positioned with respect to each other. For example, those elements which establish fiields for deflecting the beam along X and Y coordinates are desirably positioned in mutually perpendicular relationship to insure orthogonality in the beam deflection. Moreover, those forming and controlling elements which are utilized for focusing the electron beam are desirably axially aligned to insure the concentricity of the beam.

Various problems are sometimes encountered in the manufacture of cathode ray tubes with respect to the relative alignment and positioning of the internal forming and controlling elements. Accurate positioning and alignment frequently require skilled operators, expensive assembly fixtures and complex assembly operations. The utilization of support rods of ceramic material or glass, heated to a plastic condition during assembly, as in glass rodded electron guns, may produce alignment problems due to thermal contraction upon hardening of the rod material. In addition, any welding operations which may have to be performed to strap electrodes to rigid support rods can In order to cope with the foregoing problems, a cathode ray tube has been developed wherein the internal elements are supported in a surrounding ceramic tube coaxial with the tube envelope. The elements have conductive pins which project into elongated slots in the tube, and the elements are spaced axially from each other in the tube by annular ceramic spacers. A cathode ray tube of such contruction is described in US. Pat. No. 3,354,339 issued to the inventor of the present invention.

Certain types of cathode ray tubes may have internal elements of different transaxial size (diameter). For example, where convergence lens elements are used, it is desirable to maximize their diameter, consistent with other factors, to reduce lens distortions (the electrons thereby passing through only the central or uniform part of the lens field). Also, in a shape beam tube, the matrix plate result in misalignment and position variation due to therhaving shaping apertures therein may often be of large transaxial size to more readily accommodate a large number of apertures. Other internal elements, however, are usually better if smaller, since their focusing effect is thereby enhanced. Another example of a tube in which internal elements of different diameter are present is the scan converter tube, which includes a dielectric storage surface and sometimes several parallel mesh electrodes. For good resolution, it may be advantageous to make the storage surface and mesh electrodes large, Whereas, the other elements (comprising two opposing axially aligned electron gun on opposite sides of the storage surface) are often kept small for higher sensitivity of the deflection means.

In cathode ray tubes having internal elements of different diameter, supporting all the elements with a ceramic tube as described in the above cited patent may not be possible without encountering difiicult assembly techniques. This may result in excessive manufacturing costs.

It is an object of the present invention to provide an improved cathode ray' tube.

Another object of the invention is to provide a cathode ray tube wherein accurate positioning and alignment of internal elements is assured.

It is a further object of the invention to provide a cathode ray tube which is readily assembled and of rugged construction.

Still another object of the invention is to provide an improved cathode ray tube wherein internal elements of different transaxial size are readily accommodated.

Other objects of the invention will become apparent to thos skilled in the art from the following description taken in connection with the accompanying drawings wherein:

FIG. 1 is a side view of a cathode ray tube constructed in accordance with the invention, with the cathode ray tube envelope being shown in full section;

FIG. 2 is an enlarged offset exploded perspective view of internal elements in the cathode ray tube of the invention;

FIG. 3 is an enlarged exploded perspective'view of a ceramic tube forming part of the cathode ray tube and which is used to support the internal elements illustrated in FIG. 2;

FIG. 4 is an enlarged exploded perspective view of a clamp arrangement utilized for holding together the two separable parts of the ceramic tube of FIG. 3.

FIG. 5 is a full section schematic view of part of a further embodiment of the invention; and

FIG. 6 is a perspective view of a clamp arrangement used in the embodiment of FIG. 5.

Very generally, the cathode ray tube of the invention includes an envelope 11 and a plurality of internal elements 21-28, etc. A tube 12 of ceramic or other electrically non-conductive material surrounds and supports the internal elements, at least one of which (38, 39, 41)

is of greater transaxial size than the others. The nonconductive tube has an axially separable enlarged portion 53 which accommodates the larger internal elements.

Referring now more particularly to FIG. 1, a cathode ray tube constructed in accordance with the invention is illustrated. The illustrated tube is a shaped beam tube of the type in which an electron beam is shaped in a desired cross section, such as a letter or number, by pass ing the beam through a correspondingly shaped aperture. The cathode ray tube consists of a glass envelope 11 having a larger section 13 and a constricted elongated neck section 14. The two sections 13 and 14 are joined by a web 15. One end of the larger section 13 is closed by a glass face plate 16, the interior surface of which is coated by a suitable light emissive material 17 so that a visual display will be produced upon impingement of electrons on the material 17.

The end of the neck section 14 opposite the larger section 13 is closed by a glass cap 18 through which a plurality of pins 19 pass. Suitable electrical connection, not illustrated, is made from the pins to forming and controlling elements in the electron gun assembly.

Although the invention is applicable to other types of cathode ray tubes, the particular tube illustrated, and the particular type of electron gun illustrated, are for producing a graphical display with alphanumeric reference characters. It is to be understood, however, that the invention is applicable to other types of cathode ray tubes and electron guns, as will become apparent to those skilled in the art from the description herein.

Referring now particularly to FIG. 2, the beam forming and controlling elements will be explained. Electrical aspects of their operation and of the circuits with which they are associated are not described herein, as such details are not critical to the invention. The general function of each of the elements will, however, be given.

The electron beam originates at a cup shaped cathode 21 which surrounds a heater 22. The cathode may be comprised of nickel coated with barium oxide or some other similar material which produces free electrons at elevated temperatures. Such electrons are directed into a beam by elements which are maintained at a positive potential with respect to the cathode and which will be explained subsequently. A cup shaped grid element 23 surrounds the cathode. The potential of the grid 23 is controlled so as to control the number of electrons in the beam.

The beam thus produced is accelerated and focussed by a series of electrostatic lenses 24-28L These lenses are cylindrical in shape and are hollow to permit the electron beam to pass therethrough. As is known in the art, the lenses 24-28 are maintained at a predetermined potentional with respect to the cathode to produce a desired electron focus.

After leaving the lens 28, the electron beam is passed through three successive pairs of selection plates 31, 32 and 33. Each platein the pairs 31, 32 and 33 is connected across the ends of a cylindrical segment 34, the purpose of which will be subsequently explained. A field is established between the plates in each pair and is regulated to suitably deflect the beam in a desired manner. In the particular gun shown, the pairs of plates 31, 32 and 33 deflect the beam to select a particular aperture in a matrix 36. The matrix, as explained below, shapes the beam in accordance with a desired alphanumeric character or desired graphical line segment. The plate pairs 31 and 33 are for accomplishing vertical deflection of the beam and the plate pair 32 is for accomplishing horizontal deflection of the beam.

The matrix 36 comprises an electron opaque plate, not illustrated, in which the previously mentioned plurality of apertures are formed. The apertures correspond to the shape of alphanumeric characters or to the shape of graphical line segments, and shape the beam as it passes therethrough. Deflection of the beam may thereby be accomplished by plates 31, 32, 33 to select a particular desired aperture and select the shape of a particular image to be displayed upon the screen of the cathode ray tube. Of course, other shapes are also possible, depending upon the desired display. The matrix 36 is supported at the end of a matrix cylinder 37. The cylinder 37 is hollow to permit the electron beam to pass therethrough.

Three electrostatic lenses 38, 39 and 41, are positioned to converge the electron beam and direct the electron beam toward the axis as it leaves the matrix 36. The lenses 38, 39 and 41 are hollow metal cylinders, and the lens 38 extends over the end of the matrix cylinder 37 and over the matrix 36. The lenses 38 and 39, and

7' the plate pair 43 is for horizontal deflection. Potential on the reference plates is controlled so that, after an aperture is selected by the selection plates 31, 32 and 33, and the beam is returned toward the axis by lenses 38, 39 and 41, the beam is returned to a path parallel to and on the axis by the reference plates 42, 43 and 44.

Final focusing of the electron beam on the screen 17 is accomplished by a series of electrostatic lenses 47, 48 and 49. The lens 49 consists of elongated hollow metal cylinders of different diameters joined by a flange 51. Final deflection of the axial electron beam to a desired position on the screen 17 is accomplished by an electromagnetic deflection yoke (not shown) external to the tube, after the beam exits the final lens element 51.

Operation of the device just described may be carried out in accordance with known techniques. By way of example, the following potentials are typical for the various elements during operation of the cathode ray tube:

Cathode 21: -300 volts with respect to ground Heater 22: 6.3 volts AC Lenses 24, 26, 28, 37 and 41: 0 volt with respect to ground Lenses 25 and 27: 1800 volts with respect to ground Lens 38: volts with respect to ground Lens 39: -2200 volts with respect to ground Lens 47: 0 volt with respect to ground Lens 48: -200 volts with respect to ground Lens 49: +1000 volts with respect to ground Material 17: 19,000 volts with respect to ground The various elements of the electron gun are supported within the elongated cylindrical ceramic tube 12, illustrated in FIG. 3. A portion intermediate the ends of the tube 12 is of enlarged diameter (transaxial size) and is indicated at 53. This enlarged portion is for accommodating the larger diameterlenses 38, 39 and 41. The tube is separable at the enlarged portion 53 into two sections 54 and 56. Although the tube 12 is preferably of ceramic material, other electrically non-conductive material having structural strength may be satisfactory.

Circumferential positioning of the various elements of the electron gun is accomplished by a plurality of pins 57 (see FIG. 2) which cooperate inelongated slots 58 in the ceramic tube 12. The pins are attached to the elements by suitable means, such as welding, and are made of electrically conductive material. The pins extend radially outward from the cylindrical elements of the electron gun into respective slots 58, and protrude a slight distance beyond the outer surface of the ceramic tube 12. Suitable electrical connection may be made to the elements through these pins from the various connector pins 19.

The circumferential positioning of the slots 58 and the positioning of the pins 57 on the various elements may be selected so that the elements are properly oriented within the tube. For example, the plates 42 must extend in a direction perpendicular to the plates 43. Accordingly, the pins on the cylindrical segments 46 attached to the plates 42 mate in slots in the tube 12 which are positioned 90 around the tube with respect to those slots in which the pins on the segments attached to the plates 43 extend. To hold the plates in each of the pairs the proper distance apart, means such as a suitable clip or push-on fastener (not shown) may be attached to the ends of the pins to hold the cylindrical segments 34 and 46 against the inner surface of the ceramic tube. Alternatively, the pins may be grooved at the slot in the tube.

The two portions 54, 56, of the ceramic tube are maintained in circumferential alignment by the two pins 57 on the cylinder 39. One pin 57 cooperates in a slot in 56, the other in a slot in 54, thereby preventing rotation of one portion of the ceramic tube with respect to the other.

Axial positioning of the various elements in the electron gun is accomplished by a plurality of annular ceramic spacers 61. Alternatively, the spacers may be of other electrically non-conductive materials having compressive rigidity. The spacers 61 are of an axial dimension to maintain a desired axial spacing between the various elements between which they are positioned. The elements 41 and 38 serve as reference elements, as explained be low, from which the other elements are located with respect to each other in accordance with the axial dimensions of the various ceramic spacers. The various other elements 34, 28, 27, etc., are axially located and positioned in the tube by means of the annular ceramic spacers 61. The spacers can be of any other suitable shape which will avoid interference with the beam, but they preferably mate with the interior surface of the ceramic tube to be axially aligned thereby.

The cylindrical element 39 is positioned within the enlarged portions 53 of the ceramic tube so that it extends simultaneously to both sides of the separating plane. Element 39 fits snugly in each portion 53 and thus maintains the two portions 53 in coaxial alignment.

In order to assemble the internal elements, the elements are grouped and placed in the sections 54 and 56 of the tube 12 before the sections are joined together. To assemble the elements 41, 42, 43, 44 and 47 in the tube sections 54, the lens 41, which has previously been assembled as a unit, is inserted into the enlarged portion 53 of the tube section 54 until it abuts the reduced diameter portion of the tube section 54. It may then be secured loosely I by push-on fasteners. The smaller diameter internal ele ments 42, 43, 44 and 47, with associated spacers 61, are inserted from the small end of the tube section 54 until they stop against the small end of the lens 41. They are then secured loosely by push-on fasteners.

The internal elements 23-28, 31-33, 37, 38 and 39 are assembled in the ceramic tube section 56 in a similar manner. The larger diameter elements 38 and 39, with associated spacers 61, are inserted into the enlarged portion 53 of the tube section 56 until the element 38 stops against the reduced diameter portion of the tube section 56. The elements 38 and 39 are then secured loosely by push-on fasteners. The smaller elements 37, 33, 32, 31, 28, 27, 26, 25, 24 and 23, with associated spacers 61, are inserted into the tube section 56 from the small end in the proper order and are loosely secured with push-on fasteners. When all the internal elements have been placed in the tube section 56, the grid-cathode-heater assembly 21, 22, 23 is positioned axially by welding the pins 57 extending from the grid 23 to a snap ring, not illustrated. The snap ring fits into an annular groove 60 near the small end of the tube section 56. The other small internal elements 24, 25, 26, 27, 28, 31, 32, 33 and 37 with their associated spacers, are pushed against the element 23 until the entire column is tight. The push-on fasteners of all the elements may then be tightened.

At this point, the two sections 54 and 56 of the ceramic tube 12 are joined at the separable enlarged portion 53. The means for accomplishing the joining are subsequently described. The axial position of the elements within the section 54 may then be established by moving them toward the larger internal element 39 and then tightening the push-on fasteners. Alternatively, the larger internal element 41 may be moved until it stops against the smaller diameter portion of the section 54 and may then be secured by tightening the push-on fasteners. The smaller elements 47 and 48 may then be moved toward the element 41 until they are tightened against the element 41. Their push-on fasteners may then be tightened.

The lens element 49 is then inserted into the small end of the tube section 54 until the end of the tube section abuts the flange 51. The connecting pins 57 of the lens element 49 may then be secured by welding to a suitable snap ring, not illustrated, which fits in the annular groove 55 near the small end of the ceramic tube section 54.

The use of push-on fasteners on the pin 57 to hold cylindrical electrodes 24-28, 37-39, 41, 47, and 48 in position is optional. Push-on fasteners are a convenient means of retaining the cylinders in position until assembly is complete, but are not necessary. Push-on fasteners are required however on the pins 57 of the electrodes 31-33 and 42-44 to retain their segments 46 against the inner wall of the ceramic cylinder.

Although as described above, axial positioning of the reference elements 41 and 38 is accomplished by having the reference elements engage one or both of the smaller portions of the corresponding tube sections 54 and 56, axial reference may be accomplished in any other suitable manner.

For example, axial location may be accomplished by selecting a suitable length for certain of the slots 58. The pins 57 on the reference elements selected may then be used to locate the reference elements by bottoming in the corresponding slots. Axial location of the other elements may be made from the reference elements by means of the ceramic spacers 61.

The particular way in which the elements are axially and circumferentially located within the tube facilitates assembly of the gun. This is because the elements are installed and positioned in accordance with the pins which extend therefrom into the appropriate slots in the tube. Positioning and support of the beam forming and controlling elements can therefore be accomplished by unskilled operators and require no elaborate fixtures or equipment. The fact that the tube is separable into the two sections 54 and 56 facilitates the positioning of the larger lenses 38, 39 and 41 within the tube. No welding or similar types of attachment is necessary and, because the ceramic tube and the various elements of the gun may remain cool during assembly, no problems of thermal expansion and contraction are encountered. Dimension tolerances may thereby be maintained more accurately and more easily.

In order to hold the two separable sections 54 and 56 of the ceramic tube 52 together, a lever operated clamp arrangement is utilized. This arrangement consists of a pair of annular rings 62 and 63 which fit over the smaller portions of the ceramic tubes and abut the ends of the larger portion 53 thereof. A plurality of levers or snubbers 64 are attached to the rings 62 and 63 and extend radially outward. A plurality of wires 66 extend between the rings 62 and 63. The ends of the wires bend inwardly and are attached to the rings. The wires pass on either side of the larger portion 53 of the ceramic tube.

The snubbers have curved ends are of resilient materaial and have openings 65 therein through which the respective wires 66 pass. When the snubbers are urged inwardly toward each other, they bend in a manner such that an effective fulcrum exists at each point of attachment of the snubbers to the rings. When each snubber engages the wire which passes through it, it applies tension 7 upon the wires as a lever and this force is transmitted at the fulcrum point to the ring. The forces on the rings at the fulcrum points urge the rings toward each other. This clamps the two separable halves of the tube securely against each other at their interface.

The resilient snubbers 64 are selected to be of a dimension which serves to locate and mount the ceramic tube 12 within the constricted portion 14 of the cathode ray tube envelope 11. The snubbers 64 resiliently engage the inner surface of the neck 14 and are sufficiently spaced from each other to support the ceramic tube within the neck. The snap rings, not illustrated, in the grooves 55 and 60 at the ends of the ceramic tube may be provided with snubbers similar to the snubbers 64 but appropriately larger to engage the tube envelope to further support the ceramic tube within the tube envelope.

Referring now to FIG. 5, an alternative embodiment of the invention is shown schematically. The embodiment of FIG. is a scan converter tube such as have application in bright radar display systems. A tube of this general type includes a centrally disposed storage surface and means for producing two oppositely directed electron beams, one on each side of the storage surface. One beam serves to store information on the storage surface, and the other beam serves to scan the storage surface to derive information therefrom. The writing beam may be deflected by radar signals consisting of range, aximuth, and video information and the tube may, for example, utilize a rotating yoke. In radar systems, seconds are typically required to complete one rangeazimuth scan in synchronism with the rotation of the radar antenna. The reading beam of a scan converter tube, on the other hand, may operate in the standard 525-line TV raster mode, completing a scan in of a second. Video information from the reading beam is then displayed at high brightness and a high refresh rate on a standard TV monitor.

The illustrated scan converter tube includes a glass envelope 71 having an enlarged central portion 72 and a pair of smaller diameter neck portions 73 and 74 extending in opposite directions from the central portion axially thereof. A ceramic tube 76 is positioned within th envelope 71 and comprises a central enlarged section 77 and a pair of smaller diameter sections 78 and 79 extending therefrom. The central portion 77 is contained within the enlarged portion 72 of the envelope, and the narrower diameter sections 78 and 79 are contained within the smaller diameter portions 73 and 74 of the envelope. The ceramic tube is separable along an interface 81.

As was the case in the previously described embodiment, the ceramic tube 76 is for supporting the various internal elements of the cathode ray tube. Although not specifically illustrated in FIG. 5, it is to be understood that the various internal elements, as described subsequently, are supported within the ceramic tube in a manner identical with that described in the various embodiment. Thus, the internal elements may be provided with pins extending therefrom through corresponding axial slots in the surrounding ceramic tube and may be secured therein by push'on fasteners or other suitable means.

A storage surface 82 is positioned transversely of the axis of the cathode ray tube within the central enlarged portion 77 of the ceramic tube 76. The storage surface 82 may be of any suitable construction to provide for storage of information in accordance with the impingement of an electron beam thereon. A collector layer 83 is positioned adjacent to and parallel with the storage layer 82. Decelerator grids 84 and 86 extend parallel with the collector and storage layers on opposite sides thereof. Each of the storage and collector layers and the decelerator grids may consist of mesh discs mounted in hollow metal cylinders 85 of large diameters. The mounting cylinders are spaced from each other by suitable annular ceramic spacers 87. The ceramic spacers 87 are of the same configuration and used for the same purposes as were the ceramic spacers 61 in the previously described embodiment.

In order to focus and direct the electron beam which writes information to be stored on the storage layer 82, a plurality of suitable internal elements 88, 89, 90, 91, 92, 93 and 94 are provided. Ceramic spacers 87 are used between these elements to position them axially. The element 92 may be utilized as a reference element and abuts against the shoulder between the enlarged portion 77 and the narrower portion 78 of the ceramic tube 76. Suitable grid-cathode-heater assemblies and appropriate leads and connectors, none of which are illustrated, are also provided at the end of the tube portion 78 to produce the writing beam.

The scanning beam is directed and focused by a plurality of internal elements 96, 97, 98, 99, 100, 101 and 102. Axial spacing between these elements is also maintained by ceramic spacers 87. A suitable grid-cathodeheater assembly, not illustrated, may be provided at the end of the tube portion 79 in order to produce the scanning or reading beam.

The assembly of the various items recited above may be accomplished in a manner similar to that described in connection with the previous embodiment. The advantages accruing from the construction illustrated in FIG. 5 are the same as those mentioned in connection with the previous embodiment. The enlarged portion 77 of the ceramic tube 76 readily accommodates the enlarged diameter elements and those elements are readily assembled therein, since the ceramic tube is separable long the interface 81.

Although the same general type of assembly may be utilized to secure the separable portions of the ceramic tube 76 in place as was utilized in connection with the previous embodiment, an alternative expedient is illustrated in FIG. 5 and is also shown in FIG. 6. A sleeve or cylinder of resilient material which is split axially is snapped over the enlarged portion 77 of the ceramic tube 76 to secure the two separable portions of the tube together axially. A preferred material for the cylinder 103 is molybdenum. A plurality of resilient snubbers 104 are circumferentially distributed about the cylinder 103 at the ends thereof to engage the inner surface of the tube envelope 71. This positions and supports the ceramic tube 76 within the glass envelope 71. For further support, resilient snubbers 106 may be provided in snap rings 107 and 108 which mate in corresponding grooves at the respective ends of the ceramic tube 76. The snap rings .107 and 108 aid in mounting the grid-cathode-heater assemblies, not illustrated.

Although the invention has been described in connection with cylindrical beam forming and controlling elements and a cylindrical ceramic tube, other cross sectional configurations may be utilized within the scope of the invention. Thus, the outer cross section of the elements and the inner cross section of the ceramic tube may be square, hexagonal, etc. The mating of the forming and controlling elements with the tube may thereby serve to circumferentially position the elements as well as hold them in alignment.

It may therefore be seen that the invention provides an improved electron gun assembly for a cathode ray tube wherein accurate positioning and alignment of various elements of the gun is assured. The gun is readily assembled and is of rugged construction. Certain elements of the gun which are of different transaxial size than the other elements are readily accommodated in the gun construction.

Various embodiments of the invention other than those shown and described herein will become apparent to those skilled in the art from the foregoing description and accompanying drawings. Such other embodiments, and modifications thereof, are intended to fall within the scope of the appended claims.

What is claimed is:

1. A cathode ray tube comprising, a tube envelope, a plurality of internal elements positioned within said errvelope, at least one of said internal elements being of substantially greater transaxial size than the others, an electrically non-conductive tube of two separable parts surrounding said elements for supporting said elements in said envelope, said non-conductive tube having an enlarged portion for accommodating said internal elements of greater transaxial size and being axially separable at said enlarged portion, and means for securing the separable parts of said non-conductive tube together.

2. A cathode ray tube in accordance with claim 1 wherein said internal elements have outer surfaces engaging the inner surface of said non-conductive tube to maintain axial alignment of said internal elements.

3. A cathode ray tube in accordance with claim 2 wherein said internal elements have pins projecting outwardly thereof and wherein said non-conductive tube has elongated slots therein receiving said pins to locate and support said internal elements circumferentially with respect to each other.

4. A cathode ray tube in accordance with claim 1 wherein electrically non-conductive spacers are provided between said internal elements to maintain the relative axial position of said internal elements.

5. A cathode ray tube in accordance with claim 1 wherein said internal elements and said non-conductive tube are of ceramic material and are hollow and cylindrical, said internal elements having outer diameters mating with the inner diameter of said ceramic tube, wherein a plurality of annular ceramic spacers are each positioned between respective elements, wherein said internal elements have pins projecting outwardly thereof, and wherein said ceramic tube has elongated slots therein receiving said pins, said pins projecting through said slots and being electrically conductive.

6. A cathode ray tube in accordance with claim 1 wherein said securing means comprise a pair of clamp tion of said non-conductive tube, and lever means secured members disposed on opposite ends of said enlarged por- 40 to said clamp members and adapted to engage the inner surface of said envelope to be displaced thereby and urge said clamp members toward each other.

7. A cathode ray tube in accordance with claim 6 wherein said lever means comprise a plurality of resilient snubbers extending radially from said clamp members, said snubbers being adapted to engage the inner surface of said envelope and support said non-conductive tube with respect to the said envelope.

8. A cathode ray tube in accordance with claim 1 wherein said internal elements of greater transaxial size include at least one electrostatic electron lens.

9. A cathode ray tube in accordance with claim 1 wherein said internal elements of greater transaxial size include a target surface.

10. A cathode ray tube in accordance with claim 1 wherein said securing means comprise a resilient cylindrical sleeve disposed coaxial with said non-conductive tube about the outer surface of said enlarged portion, and a plurality of resilient levers engaged in aperatures adjacent each end of the cylindrical sleeve.

11. A cathode ray tube in accordance with claim 8 wherein one of said internal elements is a beam shaping member comprising a plate of electron opaque material perforated by a plurality of character shaped apertures.

References Cited UNITED STATES PATENTS 2,496,825 2/1950 Szegho 313-82 3,047,759 7/ 1962 McNaney 313-82 3,277,328 10/ 1966 Borman 313-82 3,349,270 10/ 1967 Bell 313-82 X 3,354,339 11/1967 Bell 313-82 JAMES W. LAWRENCE, Primary Examiner V. LAFRANCHI, Assistant Examiner US. Cl. X.R.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Pat t N 0 99 Dated September 15, 1970 Inventor(s) Alexander B911 It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 1, lines 5 and 6 for "assignor to Stromberg Datagraphics,

Incfl', read "assignor to Stromberg DatagraphiX, Inc."

Column 2, line 16 for "shape", read "shaped".

Column 2, line 27 for "gun", read "guns".

Column 4, line 42 for "-300", read '-3000".

Column 7, line 57 for "various", read "previous".

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